1. Field of the Invention
The present invention relates to a vehicle seat, and in particular relates to a vehicle seat of the type provided with: a seat lifter mechanism (i.e. a seat height mechanism) for effecting adjustment in height of the seat; and a tilt mechanism for causing a forward end portion of seat cushion of the seat to tilt or incline adjustably in a vertical direction.
2. Description of Prior Art
Among various vehicle seats, known is a vehicle seat so designed to enable a user to adjustingly raise and lower the seat by operation of a seat lifter mechanism provided in the seat, and also enable the user to adjustingly tilt or incline a forward end portion of seat cushion of the seat vertically by operation of a tilt mechanism provided in the seat.
For example, the Japanese Laid-Open Patent Publication No. 2008-105542 (or JP 2008-1005542 A1) teaches this kind of seat. According thereto, the seat is equipped with a seat lifter mechanism by which a seat cushion of the seat may be raised and lowered, with the seat cushion itself being maintained in a substantially horizontal state. Also, the seat is equipped with a tilt mechanism by which a forward portion of the seat cushion may be tilted vertically, wherein such forward portion of seat cushion is provided with a tiltable frame or the so-called “tilt pan” therein.
The tilt mechanism comprises: a link member having a forward end pivotally connected to a forward portion of the afore-said tilt pan; a lead screw; a nut member threadedly engaged with the lead screw; and an electric motor operatively connected with the nut member. The link member is at the rearward end thereof pivotally connected to a forward end of the lead screw. Operation of the motor causes rotation of the nut member which in turn causes translation of the lead screw, and the link member connected between the lead screw and tilt pan is thereby moved, so that the tilt pan may be adjustingly tilted or inclined in the vertical direction.
The seat lifter mechanism comprises; four links pivotally connected between the seat cushion and a floor side; a lead screw operatively connected with the rearward end portion of one of the four links; a nut member threadedly engaged with the lead screw; and an electric motor operatively connected with the nut member. Upon operation of the motor, the nut member is rotated to cause translation of the lead screw connected with one of the four links, thereby causing all the four links to move vertically, so that the seat cushion may be adjustingly raised and lowered.
However, the above-described seat has been with the problem that the seat lifter mechanism and tilt mechanism are provided independently of each other, as a result of which, it is necessary to arrange spaces for accommodating each of the two mechanism in the seat cushion, and further, for that purpose, additional parts and elements are required. Thus, with this prior art, it is difficult to reduce spaces for those two mechanisms to widen a space in the seat cushion, and the seat cushion can not be assembled rapidly and economically with a small number of parts.